A TEST OF NATURAL SELECTION ON ALPHA-GLOBIN VARIATION

用于在分子水平上检测自然选择的统计方法的发展，使得研究形成DNA序列变异模式的进化力量，以及一个位点的选择影响连接的中性位点的变异模式的基因组尺度成为可能。本研究以鹿鼠（Peromyscus maniculatmx）自然种群为模型系统，探讨选择、重组和基因流在形成高海拔生理适应下DNA序列变异模式中的共同作用。本研究将涉及分布在北美西部山区陡峭海拔梯度上的P. maniculatw种群的双位点a-珠蛋白多态性的分子遗传学分析。安迪的目标是：(1)通过对三个不同海拔样带取样的小鼠进行调查，记录马丘尼弓形虫a-珠蛋白基因区域序列变异的地理模式；(2)使用一系列新开发的统计方法检验a-珠蛋白变异的自然选择证据；(3)确定相对于两个紧密相连的a-珠蛋白位点之间的重组率的上位选择强度；(4)确定a-珠蛋白变异的选择强度相对于高、低海拔人群间的基因补偿流率。这项研究将为在DNA序列水平上研究重要生化表型的适应性变化提供一个独特的机会。

The development of statistical methods for detecting natural selection at the molecular level has made it possible to investigate the evolutionary forces that shape patterns of DNA sequence variation, and the genomic scale at which selection at one site influences patterns of variation at linked neutral sites. The purpose of the proposed study is to use natural populations of the deer mouse, Peromyscus maniculatmx as a model system to investigate the joint effects of selection, recombination, and gene flow in shaping the pattern of DNA sequence variation underlying physiological adaptation to high altitude. This study will involve a molecular genetic analysis of a two-locus a-globin polymorphism in populations of P. maniculatw that are distributed across steep elevational gradients in montane regions of western North America. The objectives of the Andy are (1) to document geographic patterns of sequence variation in the a-globin gene region of P. maniculatus by surveying mice sampled across three separate elevational transects; (2) to test for evidence of natural selection on a- globin variation using an array of newly developed statistical methods; (3) to determine the strength of epistatic selection relative to the rate of recombination between the two closely linked a-globin loci; and (4) to determine the strength of selection on a-globin variation relative to the rate of countervailing gene flow between high and low-altitude populations. This study will provide a unique opportunity to investigate adaptive variation in an important biochemical phenotype at the DNA sequence level.